In the reconstruction of soft tissue defects in humans and animals, such as in abdominal hernia repairs, surgical mesh is often used to reinforce the soft tissue defect so as to facilitate healing and to prevent subsequent defect recurrence. More particularly, when performing a closure of a soft tissue defect in an anatomical wall (e.g., to repair an abdominal hernia), it is common to secure a surgical mesh to the soft tissue at the edge of the soft tissue defect, with some overlap between the surgical mesh and the soft tissue, so as to increase the healed strength of the surgical repair. The surgical mesh is typically secured to the soft tissue adjacent to the soft tissue defect with suture or tacks.
In practice, and looking now at FIGS. 1-3, in open procedures the soft tissue reconstruction is typically carried out using a “skirted” surgical mesh 5. Skirted surgical mesh 5 generally comprises a base layer 10 of surgical mesh terminating in an outer edge 12, and a continuous “skirt” or rim 15 of surgical mesh terminating in an outer edge 17 and an inner edge 18 which defines a central opening 19. Continuous skirt or rim 15 overlies the outer portion of base layer 10 (e.g., so that outer edge 17 of continuous skirt or rim 15 is substantially aligned with outer edge 12 of base layer 10), and continuous skirt or rim 15 is secured to base layer 10 only at or adjacent to outer edge 17 of continuous skirt or rim 15, such that the inner portions of continuous skirt or rim 15 (i.e., the portions adjacent to inner edge 18) can be lifted away from base layer 10 when desired. As a result, continuous skirt or rim 15 provides an easily accessed section of surgical mesh which facilitates fixation of skirted surgical mesh 5 to the soft tissue, i.e., by fixing continuous skirt or rim 15 of skirted surgical mesh 5 to the edges of the soft tissue defect using conventional suture or tack fixation. By providing skirted surgical mesh 5 with the continuous skirt or rim 15 of mesh material, when skirted surgical mesh 5 is being secured to the soft tissue, the sharp ends of the fixation elements (e.g., the suture needle or tack) are isolated from the delicate internal organs of the patient by base layer 10, whereby to prevent inadvertent damage to the delicate internal organs of the patient.
However, it has been found that when pulling up on continuous skirt or rim 15 of skirted surgical mesh 5 (e.g., for suturing and/or tacking), this pulling up of the continuous skirt or rim 15 can cause base layer 10 to distort significantly (e.g., to transform from a smooth planar configuration to a curved configuration, such as is shown in FIG. 4). Such distortion in base layer 10 of skirted surgical mesh 5 can make it difficult to provide a flat, symmetrical repair which is smooth and comfortable for the patient. More particularly, the configurations of surgical mesh used in these types of soft tissue repairs (e.g., the hernia meshes used in abdominal hernia repairs) are normally circular or oval in shape (FIGS. 2-4 show exemplary surgical meshes which are oval in shape) and can possess very tight radii, particularly at the longitudinal ends 25 of oval skirted surgical meshes 5 (see FIGS. 2 and 4). As the radii of continuous skirt or rim 15 of skirted surgical mesh 5 becomes tighter, the effect of “pulling up” on the continuous skirt or rim 15 of skirted surgical mesh 5 (e.g., with graspers 30, FIG. 4) is increasingly distorting to base layer 10 of skirted surgical mesh 5.
Efforts have been made to reduce this distortion of base layer 10 of skirted surgical mesh 5 when pulling up on continuous skirt or rim 15 of skirted surgical mesh 5.
In one such effort, and looking now at FIG. 5, the inner edge 18 of continuous skirt or rim 15 is scalloped (i.e., a portion of inner edge 18 of continuous skirt or rim 15 is recessed, such as is shown in FIG. 5 at 40, from the remainder of inner edge 18 in an effort to minimize the distortion of base layer 10 of skirted surgical mesh 5 when pulling up on continuous skirt or rim 15 of skirted surgical mesh 5. Unfortunately, in practice, this approach has proven to be of limited benefit.
In another such effort, and looking now at FIG. 6, a surgical mesh 45 is provided which comprises a base layer 50 of surgical mesh which is completely covered with a top layer 55 of surgical mesh, with top layer 55 being secured to base layer 50 about the outer edge(s) 60 of the two layers, and with top layer 55 being bifurcated at 65 so as to provide two separate pockets of surgical mesh. Then, during use, a first half of top layer 55 of surgical mesh 45 is pulled upward for fixation (e.g., by gripping the first half of top layer 55 with graspers 30 at the bifurcation line 65) and then the second half of the top layer 55 of surgical mesh 45 is pulled upward for fixation (e.g., by gripping that second half of top layer 55 with graspers 30 at bifurcation line 65). Unfortunately, this construction still suffers from distortion of base layer 50 when one or both halves of top layer 55 of surgical mesh 45 is drawn upward for fixation.
Thus there is a need for a novel surgical mesh which provides a skirt or rim of surgical mesh about the outer perimeter of a base layer of surgical mesh but which allows the skirt or rim of surgical mesh to be pulled upward without distorting the smooth planar configuration of the base layer of surgical mesh.